花形是指（）的形态，即花瓣在花托上组合排列成的状况。
A.花序
B.花冠
C.花朵
D.花葶
参考答案：B
国际上公认的基尼系数警戒线为0.5。
After two months' hard work, the workers managed to connect the two towns railway. [ ]
A. under
B. by
C. in
D. up
